I recently bought a second hand Hartke HA3000 head and VX410 and VX115 cabs. On the back of the cabs are 8Ohm unputs and an extension output.

I was wondering if anyone knows if i plug both of the cabs into the amp, or plug the VX410 into the amp and the VX115 through the extension of the VX410.

I think you use the extension on from the other cab. Im also wondering this, If my amp problem doesnt sort it self out soon ill probably end up getting hartke them being my second main choice.
Yamaha TRB1006
Fender MIA jazz bass
Hora Hybrid double bass
Hartke lh 500
Ev 606L
Epiphone les paul
thats what i thought, if i do that, will it be in parallel?

btw, hartke are awesome!